Definition 5 (Appendix B, [1]}) 
An o-minimal structure is a collection
\(\mathcal {S}=\lbrace \mathcal {S}_n\rbrace _{n=1}^{\infty }\) , where each \(\mathcal {S}_n\)  is a set of subsets of \(\mathbb {R}_n\)  satisfying the
following conditions:
1. \(\mathcal {S}_1\)  is the collection of all finite unions of open intervals and points;
